The present invention relates to an improved cushioned shipping bag and a unique method for continuously making such bag. Cushioned or padded shipping bags are used for mailing or shipping articles such as books, plastic products and other items which might be damaged or injured if not handled carefully and safely.
Numerous types of cushioned or padded shipping bags have been developed and currently are being used today. One such bag, known as the "trapped air bubble" bag, has a layer of relatively stiff paper material on the outside and two layers of a thin plastic sheet material inside, the two layers of plastic material having manufactured and trapped inbetween them a plurality of air bubbles. The air bubbles are uniformly spaced on the plastic material. That bag is relatively inexpensive and of a relatively light weight, but has numerous disadvantages which the present invention overcomes. For example, during handling, it is relatively easy to puncture the trapped air bubbles in the plastic layers of the bag, thus leaving the objects placed inside the bag with little or no protection. Also, where the inside plastic layers with the trapped air bubbles are folded at the corners of the bag and the bag is sealed along its edges, the air bubbles are broken along those edges thus again offering little or no protection against damage.
Further, little protection for the objects in the trapped air bubble bag is provided by the thin plastic film between the air bubbles. For example, if a sharp corner of some foreign object were to be placed against or strike the bag in the spaces between the air bubbles, the sharp object would impinge directly upon the objects inside the bag.
Moreover, the trapped air bubble layer is thin and flexible and in order for the bag itself to be relatively stiff and thus be strong enough to be handled in a normal fashion, the paper on the outside of the bag has to be relatively thick, such as on the order of 60 pounds per ream. Also, the trapped air bubble bag is relatively easy to tear. Once a tear break is formed in the outside surface, that tear can spread easily through the bag thus possibly leading to the injury or destruction of the objects inside it.
Another carrier bag that is in use today has as the cushioning material, paper waste, finely divided paper material, cotton waste, fabric waste, or the like. The waste is used as a filler and is placed between two sheets of paper. The paper is then folded and the edges sealed forming a bag. That bag also has numerous disadvantages which the present invention overcomes, however. For example, the stuffing is relatively uneven and the final bag has a rough or wrinkled outer surface on many occasions. Also, in order to prevent the outside layer of the bag from being punctured and the filler from escaping, the bag is made from relatively thick paper, on the order of 60 pounds per ream. The filler itself is loosely held inbetween the paper layers and once the bag is punctured, can escape and create an unsightly mess. Some waste fillers are of a very fine texture and, if the bag is accidently punctured and the filler falls on carpeting or similar surfaces, it is difficult to clean up.
Again, like the trapped air bubble bag, the filler-type bag is relatively easy to tear and thus often exposes its contents to damage or injury. Further, when the filler-type bag is compressed at the edges in order to seal them to form the completed bag, the cushioned layer is compressed to such an extent that it has the same effect as merely a third layer of paper and thus the bag itself provides limited protection at the corners and edges.
Another bag utilizes one or more layers of corrugated paper as the cushioning layer. The corrugated layers are placed between two layers of relatively thick paper and the bags are cut and formed from the laminate. That bag, however, has many of the same disadvantages that the trapped air bubble bag and the filler-type bag have. The corrugated-type bag is susceptible to damage along its edges and to puncture on its surfaces.
A bag having a foamed plastic liner has been introduced, but without significant success. To make that bag, a paper envelope blank is cut from the roll stock and a piece of foamed plastic is cut from the plastic stock. The two layers are then positioned one on top of the other and affixed together in some manner, such as by gluing. The bag blank is then folded to form the completed bag. Such bags do not lend themselves to high volume continuous production, and consequently, they are not commercially competitive with the trapped air bubble bag or the filler-type bag. Moreover, difficulties inherent in their design result in non-uniform appearance; often, the plastic material protrudes beyond the edge of the bag, creating an unsightly appearance. More importantly, such bags lack protection along their bottom edge. Thus, the contents of such a bag are susceptible to being injured by items striking the bottom of the bag. Also, if the objects inside the bag have any sharp corners, the objects themselves can easily puncture the bag at the bottom, leading to their possible loss or injury.